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%I #15 May 26 2024 02:14:17
%S 3,8,1,6,8,8,3,3,8,3,3,9,6,8,5,3,0,1,3,0,1,4,1,7,9,9,7,9,7,7,7,4,5,0,
%T 3,6,4,4,3,5,8,9,8,0,2,7,4,1,8,7,6,7,5,5,3,9,5,2,9,0,6,0,4,7,6,8,9,9,
%U 4,7,6,6,0,8,8,8,1,9,7,5,8,6,9,7,5,7,0,3,7,6,1,6,4,4,2,2,8,0,6,7,9,9,7,7,1
%N Decimal expansion of the constant Product_{i=1..infinity} (1-3/(2*(i+1)))^(1/2^i).
%D D.-Z. Du and F. K. Hwang, Combinatorial Group Testing and Its Applications, World Scientific, 2nd ed., 2000; p. 37.
%e .381688338339685...
%t Exp[2*Derivative[1, 0][PolyLog][0, 1/2] - Derivative[0, 1, 0][LerchPhi][1/2, 0, 1/2]/2] // RealDigits[#, 10, 105]& // First (* _Jean-François Alcover_, Feb 19 2013 *)
%o (PARI)\p 500; prodinf(n=1,((1-3/(2*(n+1)))^(1/2^n)))
%Y A054400/4.
%K nonn,easy,cons
%O 0,1
%A _N. J. A. Sloane_, May 22 2000
%E More terms from _Jason Earls_, Jun 28 2001